Description: (Applicant's Description) The objective of the Flow Cytometry Core is to provide state-of-the-art flow cytometric analysis, cell-sorting services and immunology services to Cancer Center members. The Core laboratory consists of two flow cytometry facilities, one at the University of Colorado Health Sciences Center (UCHSC) directed by Christopher L. Reardon, PhD MD who also is overall director and the other facility at National Jewish Medical and Research Center (NJMRC) directed by John Cambier, PhD. A new source at UCHSC provides new immunological services other than flow cytometry. The presence of the Flow Cytometry Core at two sites provides Cancer Center members with convenient access to core facilities which have both technical expertise and multi-instrument capabilities in flow cytometry. In 1999, Dr. Reardon replaced Dr. Bunn as the director of this Core laboratory. Use of the Flow Cytometry Core at UCHSC is among the highest and most popular of all share cores and continues to increase. Most noted is its increase of use by 38% over the past 2 years, serving 68 different Cancer Center members over the last year. The services of the Core include analysis of cellular antigen expression, intracellular calcium and pH levels, DNA and RNA content, cell cycle kinetics, and assays of apoptosis. Single-cell cloning and sterile cell sorting is regularly done using 4-5 parameters, although both MoFlo sorters are capable of sorting on up to 9 different parameters. Confocal microscopy provides measurements of cell size by computer based micrometry, DNA/RNA content analysis, and ion movement analysis. New services include the assessment of natural killer cell, Fas-mediated and cell-mediated antigen-specific cytotoxicity with the non-radioactive euopium-chelate release assay which is measured by time-resolved fluorometry. Other new services using this technology are fluorescence-assisted phagocytosis and chemiluminescence measurements for oxidative bursts of granulocytes. Additional new services include ELISAs and T-cell hybridoma production for T cell immortalization, and cytokine assays based on ELISA, Golgi-immunostaining and elispot assays. The Core is certified by the College of American Pathologists (CAP) for analysis of clinical research trial specimens.